I too gave up on connecting what is real from the doujin and isn't, it gets kinda annoying having to figure out after a whileDoujins said it was her uncle or something I think, but I am not sure if that timeline applies to this one.
Author likes to pull selective elements from the doujins so I gave up trying to make sense of it.
Not everything in those is canon. The basic idea is similar, but he selectively chooses what is retained and what is not. As I've mentioned before, it is best to accept what the series states as canon and not make too many assumptions based on doujinshi. Plenty of things in this series are not the same, and what people consider part of the doujinshi has also been an issue (like people reading the "If" stories, or the Futoshi series, and not understanding that those are entirely unrelated).Isn't it pretty much confirmed at this point that the doujins are canon? It was stated this chapter that she had multiple partners, including adults, which is basically what the doujin are all about. Even that she is bringing multiple guys to her dinner with her dad (her sexual partners).
Back when the manga started, it was hard to tell since it all seemed rather tame, but ever since they had sex, the author seems to be just throwing caution to the wind and making multiple mentions of stuff that fit the doujins. Either that or the doujins are set in the future, but I'm guessing a not too distant one...